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Ab initio study of the influence of aggregation on the infrared spectrum of acetonitrile
Author(s) -
Mathieu Didier,
Defranceschi Mireille,
Delhalle Joseph
Publication year - 1993
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.560450620
Subject(s) - infrared , dimer , chemistry , nitrile , acetonitrile , intermolecular force , infrared spectroscopy , ab initio , antiparallel (mathematics) , ab initio quantum chemistry methods , computational chemistry , molecule , organic chemistry , physics , optics , quantum mechanics , magnetic field
With the aim of investigating the influence of direct intermolecular interactions between nitrile groups on the infrared features of nitrile polymers, vibrational frequencies and infrared intensities of acetonitrile and of its antiparallel dimer are compared. It is found that whereas frequencies are unchanged upon association infrared intensities are dramatically affected. In particular, the striking difference between the intensities of the CN stretching band measured in gas phase, on the one hand, and in the liquid, on the other, is already accounted for at the dimer level. Despite the poor reliability of absolute values of calculated intensities, it is interesting to note that consistent trends are obtained at various levels of theory. These results suggest that ab initio calculations of infrared intensities can be useful to interpret infrared measurements, thus contributing to the elucidation of molecular structure of materials. © 1993 John Wiley & Sons, Inc.